Commit de6921cc authored by Vasily Gorbik's avatar Vasily Gorbik
Browse files

s390/test_unwind: add program check context tests 



Add unwinding from program check handler tests. Unwinder should be able
to unwind through pt_regs stored by program check handler on task stack.

Signed-off-by: default avatarVasily Gorbik <gor@linux.ibm.com>
parent e7409367

arch/s390/lib/test_unwind.c

+47 −0
Original line number Diff line number Diff line
@@ -10,6 +10,7 @@ 
#include <linux/kthread.h>

#include <linux/module.h>

#include <linux/string.h>

#include <linux/kprobes.h>

#include <linux/wait.h>

#include <asm/irq.h>

#include <asm/delay.h>
@@ -119,6 +120,7 @@ static struct unwindme *unwindme; 
#define UWM_CALLER		0x8	/* Unwind starting from caller. */

#define UWM_SWITCH_STACK	0x10	/* Use CALL_ON_STACK. */

#define UWM_IRQ			0x20	/* Unwind from irq context. */

#define UWM_PGM			0x40	/* Unwind from program check handler. */



static __always_inline unsigned long get_psw_addr(void)

{
@@ -130,6 +132,17 @@ static __always_inline unsigned long get_psw_addr(void) 
	return psw_addr;

}



#ifdef CONFIG_KPROBES

static int pgm_pre_handler(struct kprobe *p, struct pt_regs *regs)

{

	struct unwindme *u = unwindme;



	u->ret = test_unwind(NULL, (u->flags & UWM_REGS) ? regs : NULL,

			     (u->flags & UWM_SP) ? u->sp : 0);

	return 0;

}

#endif



/* This function may or may not appear in the backtrace. */

static noinline int unwindme_func4(struct unwindme *u)

{
@@ -140,6 +153,34 @@ static noinline int unwindme_func4(struct unwindme *u) 
		wait_event(u->task_wq, kthread_should_park());

		kthread_parkme();

		return 0;

#ifdef CONFIG_KPROBES

	} else if (u->flags & UWM_PGM) {

		struct kprobe kp;

		int ret;



		unwindme = u;

		memset(&kp, 0, sizeof(kp));

		kp.symbol_name = "do_report_trap";

		kp.pre_handler = pgm_pre_handler;

		ret = register_kprobe(&kp);

		if (ret < 0) {

			pr_err("register_kprobe failed %d\n", ret);

			return -EINVAL;

		}



		/*

		 * trigger specification exception

		 */

		asm volatile(

			"	mvcl	%%r1,%%r1\n"

			"0:	nopr	%%r7\n"

			EX_TABLE(0b, 0b)

			:);



		unregister_kprobe(&kp);

		unwindme = NULL;

		return u->ret;

#endif

	} else {

		struct pt_regs regs;
@@ -286,6 +327,12 @@ do { \ 
	TEST(UWM_IRQ | UWM_CALLER | UWM_SP);

	TEST(UWM_IRQ | UWM_CALLER | UWM_SP | UWM_REGS);

	TEST(UWM_IRQ | UWM_CALLER | UWM_SP | UWM_REGS | UWM_SWITCH_STACK);

#ifdef CONFIG_KPROBES

	TEST(UWM_PGM);

	TEST(UWM_PGM | UWM_SP);

	TEST(UWM_PGM | UWM_REGS);

	TEST(UWM_PGM | UWM_SP | UWM_REGS);

#endif

#undef TEST



	return ret;